Experimental and numerical evaluation of the surface-localized heating capacity of the photothermal nanocomposite-incorporated knit fabrics

Personal protection and perspiration evaporation are major features of a functional clothing system intended for outdoor environment applications. The aim of this article is to investigate the dynamic performance of an advanced multifunctional textile under solar radiation. The influence of the fabric properties of the double-layer structure and the optical property of the photothermal nanocomposite based-porous membrane (polyacrylonitrile PAN/carbon nanotube CNT) on the evaporation performance were experimentally and numerically discussed. Initially, a dedicated experimental study was conducted to measure the actual evaporation performance of the functional fabric. Following this, a two-dimensional multi-fluid model, simulated using COMSOL software, is applicable to predict experimental evaporation rates with a reasonable accuracy of 90%. The results showed that the dense structure had a greater wicking-flow rate of 0.5 cm(2) s(-1) but lower evaporation performance in contrast to the permeable fabric. The incorporation of the photothermal nanofibers into the double-layer fabric structure enhanced the surface-localized heating capacity. Through the evaporation process, compared to conventional fabric, the advanced fabric structure exhibited approximately 3.5-4.4? higher outer surface temperature. We concluded that the proposed multi-layer structure has excellent potential to enhance the solar absorption efficiency in the visible range by 50% on average. Besides, the improved evaporation performance of the functional structure was 48% and 55%, respectively, under 0.6 and 1.0 sun illumination. In addition to the clothing field, this study can be extended for wide-reaching applications based on solar vapor generation systems.